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  1. #1
    Alan MacDonald's Avatar
    Alan MacDonald Guest

    Default My new model 4-108 has a seco

    My new model 4-108 has a secondary fuel filter with a return line to tank at the location that Nigel Calder shows a bleed nipple alone.

    If I open this fitting and actuate the manual lifting pump lever many times will that bleed sufficient air after a secondary filter change? Or do I have to also go through the whole injector pump bleeding procedure outlined in Perkins owners manual?

    Thanks for any advice.

  2. #2
    vincent's Avatar
    vincent Guest

    Default " Alan, I have had to deal

    " Alan,

    I have had to deal with this problem just recently. Chances are, that you can get most of the air out by just undoing that banjo bolt. I changed filters several times (underway!) and did not have to crack the high pressure injector lines. It pays to have an electric fuel pump to make things quicker.

    vincent "

  3. #3
    roy abrams's Avatar
    roy abrams Guest

    Default " my experiance with perkins 1

    " my experiance with perkins 108s (35years)is to bleed the injector pump after replacing any filters not nesassary to bleed the injector pipes. these engines are terrible with the smalest amount of air in system.
    You can try just the filter bleed. it may work it will stop running within seconds if any air was still in
    when bleeding the pump, pump away for a long time "

  4. #4
    poker casino396's Avatar
    poker casino396 Guest

    Default "***** ****** [url=""]***** 39

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  5. #5
    Join Date
    May 2006
    Location
    Florida, USA
    Posts
    103

    Default It is usually better to bleed

    It is usually better to bleed from the exit to the injector pump instead of the return line. Then for all the time it takes follow the system to the lower injector bleed then the upper. After the air has stopped coming out on the top bleed close it then open the first 2 injector lines at the injector and crank the engine until you see fuel come out. Then shut them and start it up. You may have to repeat this. It is easier on your starter if you follow through the entire procedure from the beginning instead of taking short cuts.

  6. #6
    ron o'brien's Avatar
    ron o'brien Guest

    Default "i've been working on deis

    "i've been working on deisels since 1978. i've NEVER had to open injector lines to bleed and is in fact not a good idea. the seats on the lines somtimes will not reseat on the injector leaving a leak. bleed fuel as far as the fuel rail, or fuel galley, in the injection pump and the 2200psi generated by the pump will do the rest."

  7. #7

    Default Re: It is usually better to bleed

    Got a prob with our Perk 4-154 (same as 4-108 in US) bleeding the fuel system out after filter changes. Get clear fuel to bleed-points on the hi-pres pump, and to the bleed-off rack on top of the injectors, but she just won't fire up. No glo plug in the unit, so no fuel selenoid involved. This problem has persisted for all 6 years we've owned this boat. This year much worse than last... The one thing I can't do is take the lo-pressure pump off to clean its screen - it's tight up against the cooling system manifold, and I could not get a wrench on the outlet line to the final filter, or the six holding bolts for the top cover without removing that manifold. And I get a good clear fuel flow downstream to the injector tops anyway. Thoughts?

  8. #8
    Join Date
    Sep 2006
    Location
    Posts
    70

    Default Re: It is usually better to bleed

    Hello Jake, just for the record, 4.154 is very similar to the 200 series, but a very different critter than the 4.108.

    You may want to do a compression check first, then remove the manifold and actually check the lift pump ,after 6 years I would think you'd do the obvious. I had a 4.154 run on a squirt of WD40 in 3 empty inj. holes and a compression gauge in the last hole, No S#it...and of course check the timing mark on the side of the Inj. pump with the block.Send the pump and Inj.in for R+R.. You don't have the Inj pump with internal lift pump?

  9. #9

    Default Re: "i've been working on deis

    Quote Originally Posted by ron o'brien View Post
    "i've been working on deisels since 1978. i've NEVER had to open injector lines to bleed and is in fact not a good idea. the seats on the lines somtimes will not reseat on the injector leaving a leak. bleed fuel as far as the fuel rail, or fuel galley, in the injection pump and the 2200psi generated by the pump will do the rest."
    Hmmm I find I regularly have to slacken these to see the fuel is actually flowing into the injector . I have just had such a case where with the lines completely off there was no fuel being delivered at all . I was burning my expensive batteries turning it over and nothing was delivered. Turned out a few sharp raps on the fuel pump must have freed up some stuck part in the pump and it started pumping immediately. If I had not taken these off I would not have guessed what the problem was .

    Its an easy proceedure to bleed operate the pump ,loosen bleed on filter first and look for clear fuel without bubbles of air ,then the next one loosen banjoe , put helper on hand pump then the on distributor pump loosen lower one then top one . Thats the hand pump done ,then loosen number 4 injector line and turn over with starter till fuel comes out ,lock it off and if the motor does not start do the next injector and so on .

    You do what you have to to satisfy yourself that fuel is getting through and forget the doubters
    Last edited by tytower; 12-13-2014 at 01:10 AM.

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